Detection of gene action and combining ability effects in bread wheat (Triticum aestivum L.) using line X tester scheme

For estimating the gene action and combining ability effects of some genotypes, line x tester scheme was used to have sufficient information for certain wheat traits. The current research efforts were made to assess the type of gene action (genetic effects) and combining ability of parental genotypes for yield and its contributing attributes, so that suitable crosses might be found for further analysis. This scheme was utilized for the evaluation of six lines viz. 9726, 9727, 9729, 9730, 9520, and 9521 and three tester viz. Galaxy-13, Aas-11 and Punjab-11. These parental genotypes were assessed along with their crosses in the field. Randomized complete block design was utilized with three replications. Data was recorded and analyzed with help of precise statistical methodology. Analysis of variance revealed significant difference among the genotypes for these traits under study which have direct relation with the yield. The results of line x tester analysis when partitioned into components also showed significant to highly significant differences. Among female parents, line 9726 has good general combining ability effects for plant height and also for 1000-grain weight so it was good general combiner in this regard. Line 9729 showed good general combining ability effects for spike density. Line 9521 exhibited good general combining ability effect for flag leaf area, fertile tillers per plant, spikelets spike-1, grains/ spike, seed weight spike-1 and seed yield per plant. Considering testers, the variety Aas-11 performed best for various traits. The cross-combination 9727 x Galaxy-13 was a good specific combiner for plant height. Cross 9520 x Aas-11 was good specific combiner for flag leaf area. The other cross 9521 x Aas-11 was good specific combiner for tillers per plant and spike density. 9726 x Aas-11 appeared good specific combination for spike length, number of grains / spike, grain weight / spike and grain yield/ plant with highest positive SCA effects. While the cross combination, 9726 x Punjab-11 was better spikelet per spike and 9730 x Galaxy13 is good for 1000-grain weight. It was observed that non-additive type of gene action was involved in inheritance for most of the yielding attributes like plant length, flag leaf area, grains / spike, 1000-grain weight and seed yield / plant while all other traits showed additive gene action. In this case hybrid breeding may be suggested and it would be more useful. The traits Spikelets / spike, weight of 1000 grains and fertile tillers / plant were governed through additive type of gene action. Therefore selection in earlier generations would be effective and helpful. These information would be helpful in designing successful breeding program to develop high yielding wheat genotypes.